Parts for your 2017 Ford Mondeo-Radiator cap

2017 Ford Mondeo radiator cap — is it actually a thing?

Short answer: no, there’s no traditional radiator cap fitted to the 2017 Ford Mondeo’s radiator. Ford designed this model with a closed, pressurised cooling system that uses a remote coolant expansion tank (often called a degas bottle). The pressure cap lives on that tank, not on the radiator itself.

Technical sources back this up. The Ford Owner’s Manual for the 2017 Mondeo (Engine Coolant section) instructs owners to only remove the coolant expansion tank cap when the engine is cold—there’s no mention of a radiator cap at the radiator neck. Ford’s Workshop Manual (WSM) for the Mondeo/Fusion platform, Section 303-03 Engine Cooling, describes a closed, pressurised system featuring a degas bottle and illustrates the cap on the bottle. Genuine parts catalogues list a coolant expansion tank cap for this vehicle, not a radiator cap.

Why the change? A remote, pressurised tank mounted high in the engine bay keeps the fill point above the rest of the system, helping purge air, stabilise pressure, and reduce hot spots. It also simplifies packaging because many modern radiators don’t have a neck for a cap at all. The expansion tank cap controls system pressure—just like an old-school radiator cap—allowing excess pressure to bleed back to the bottle and coolant to return as the engine cools.

So if someone’s searching for a 2017 Ford Mondeo radiator-cap, what they really need is the coolant expansion tank cap. Treat it as a service item: if the cap’s seal looks cracked, the spring feels weak, or there’s dried coolant crust around the bottle, replace it. Always remove and refit the cap only when the engine is cold. Use the exact pressure rating shown on the original cap (commonly around 135–150 kPa/20–22 psi depending on engine variant) and stick with quality OEM-spec parts. After refilling coolant, run the engine with the heater on to help purge air and recheck the level once it cools.

• Common symptoms of a failing cap: rising temps in traffic, coolant smell, overflow from the bottle, collapsed hoses after cool-down.
• During servicing, inspect the bottle for cracks and the cap seal for hardness or nicks, replace at the first sign of trouble.

Popular questions about the 2017 Ford Mondeo radiator-cap

Does the 2017 Ford Mondeo have a radiator cap?
No—there’s no cap on the radiator itself. The vehicle uses a closed cooling system with a pressurised coolant expansion tank. The cap on that tank does the pressure control job people usually associate with a radiator cap.

This setup improves air separation and keeps the fill point high, which helps reliable bleeding and temperature control.

Which cap should be replaced on a 2017 Ford Mondeo, and how often?
Replace the coolant expansion tank cap if you notice leaks, a perished seal, weak spring tension, or overheating with no other clear cause. Many technicians treat it as preventative maintenance around major cooling-service intervals.

Always match the pressure rating on the original cap and only remove it when the engine is stone cold.

What pressure rating does the Mondeo’s cap use?
It varies by engine and market, but it’s typically around 135–150 kPa (about 20–22 psi). Check the label on your existing cap and the specifications in the Owner’s Manual to be certain.

Using the correct rating helps maintain boiling margin and protects hoses, pump seals, and the heater core from overpressure.